Help with Unity assembly modding with a game

[LolHacksRule]

I'm trying to modify an old version of Sonic Dash on Android (because I need to learn more from them to take on il2cpp), I'm trying to mod the main assembly, I can modify most of it fine (after removing compiler garbage) with dnSpy, but the game won't advance beyond the loading screen if I modified it in any way (even revert my changes), when I check logcat, there's a TRUCKLOAD of errors relating to loading types from the assembly, resigning the original APK and installing it works fine so its not a hash check. Any advice?

[LolHacksRule]

Turns out dnSpy is likely the problem, updating it and resaving the assembly without changes was loaded fine by the game.

[LolHacksRule]

Yep dnSpy was the problem